Wheelchairs are well known transportation appliances enabling the infirm, disabled and unwell person to move about with greater mobility than otherwise. Essentially, wheelchairs are small, single person conveyances typified by a chair supported by two outer, large drive wheels behind the center of gravity of the user, and with two smaller swivel mounted wheels or casters located toward the front. Motive power may be supplied by an attendant pushing the wheelchair, by the user's hands and arms applied to the drive wheels, or by an auxiliary power source.
While wheelchairs following many different designs have proliferated, there have been drawbacks heretofore that remain to be solved. In order to meet the needs and demands of the physically handicapped user, wheelchairs must be versatile and easily and readily adapted to accommodate the particular body shape and size of the user. Wheelchairs must also be versatile in adapting to both ambulatory and recreational travel, and they must be sufficiently rugged and durable to provide comfortable passage over uneven and irregular surfaces.
For instance, an unsolved need has arisen for shock and vibration attentuation control for providing extended opportunities and mobility to the user. Another unsolved need has been for a universal, adjustable chassis. Yet another unsolved need has been to provide a more fully collapsible and detachable chassis for a modular wheelchair whereby the wheelchair may be disassembled and stowed in weight and volume limited areas, such as in an overhead storage compartment of an airplane.
Yet another unsolved need has been for a chassis for a modular wheelchair which may be customized to the body shape, comfort and needs of a particular patient by a therapist with simple adjustments without special skills, tools or training. One more unsolved need has been for a more universal chassis for a wheelchair with which a variety of application specific seating system designs may be readily and interchangeably used with one wheelchair chassis without any modification to the chassis or other impairment.